Insulation

[Trevethan]

Hi I am looking to insulate the aft cabin on my ferro ketch to try and reduce condensation.

I've been looking around and most people seem to use Rockwool or fibreglass sandwich and I hate the stuff.

I got to thinking that the type of closed cell foam used in campers sleeping mats might be useful. I was a bit concerned about its behaviour in a fire so I set light to a little bit from an old mat I had at home and it burned wonderfully well with huge amounts of black smoke so that fails.

However while wandering around B&Q the other day I found something called hardwood floor underlay. This stuff purports to be insulating, damp proofing and has marks on it demonstrating it won't support its own combustion. It's a closed cell product so it won't absorb moisture like rockwool or fibreglass sandwich

Its not that thick so might need two layers. Anyone have any experience with it on a boat?

Nick

 

[Piers]

At the recent MBM weekend away, we had a presentation from 3M, who have just launched a new product called Thinsulate. From the patter, it sounds quite stunning. From the uptake from the major manufacturers, even more stunning.

It is being used to overcome two problems - sound, and condensation.

Call Peter Furby of 3M Marine products (he is always willing to talk to Forum members) and explain the problem. Knowing Peter, he will be able to help. Tel - 07770 284926.

Piers du Pré
MBM Cruising Club enthusiast
www.dupre.co.uk/fsPlaydeau.htm

 

[Trevethan]

I just called and he was very helpful. The material is rather pricey, so I think I will use it in a limited amount in cold spots, i.e. around the water tanks.

Thanks for the tip.

 

[Guest]

Talk to Paul Homer about sprayed urethane foam insulation. 0800 1955641

 

[Ecartar]

Copy of my post dated Mar 16 re:INSULATION v. CONDENSATION

"My next door neighbour had a similar problem. He has a ferro-cement boat of some 12M and lives aboard year round. With very limited insulation the problem has been solved by running a modest dehumidifier on 240v shorepower around the clock. When away from the boat the unit's outlet hose is placed in the sink. I understand the unit costs around £4/week to run paying 10p unit.

In contrast, the entire deck head of my 11M Dutch Steel Cruiser is insulated with 38mm sheet and the cabin sides above deck level forward with 19mm sheet. The sides of the hull in the engine room are also insulated with 'eggbox' foam rubber sound deadening. The remainder of the hull sides and wheelhouse cabin sides are not insulated. Despite large areas of glass above decks there is virtually no condensation when staying on board or when the boat is left unattended. The boat appears very warm at all times and requires minimal heating.

Regards,

 

[chippie]

I think it is important to remember that the moisture is still around if one is not using a dehumidifier; it is just not condensing on cool surfaces.
It is probably being soaked up by absorbent things like squabs and other foam rubber. Good ventilation is important but this can also mean cold air. A bit of a dilemma !

<P ID="edit"><FONT SIZE=-1>Edited by chippie on Thu Apr 11 00:22:01 2002 (server time).</FONT></P>

 

[Trevethan]

I've been experiementing with various closed cell foams and this laminate floor underlay seems to do a pretty good job. Despite the recent warmish days and cold nights the area I insulated was much less damp to the touch so I am going with that on the bulkheads and then face it with wood.

As for ventilation I am looking at those solar powered jobs that sit on a hatch and suck of blow according to your preference.

Do you have any other suggestions for venting systems that are easy to fit and don't draw much power?

I have seen a 12 volt system to fit in the bilges that basically empties them of air and gives a through draft. It uses a humidistate to turn on and off and I have a feeling in my boat at least it would want to run all the time!

 

[Guest]

I have a steel ebbtide 33 which has sprayed foam insulation under ply sheeting she has 3 large dorade vents and is always bone dry all through the winter when left. In very cold weather when I am on board There is some condensation on the hatch above my bunk. However I have been told that the foam is toxic if burned. Just recently I did some welding and some started to smoulder and it was very smelly so I am going to replace the parts I have removed with bubble wrap plastic sheeting.